He should pull the foreskin back when he takes a shower and wash the head of the penis and the underside of the foreskin. This should take care of any cleanliness problems. Having a foreskin actually makes having sex easier I have read because the head is more moist and softer and the foreskin makes entry into the vagina easier as well as sliding in the vagina. Having the foreskin and a more sensitive head probably will make sex feel better for him.